There has been known an image-reading device comprises a conveying unit and a reading unit.
The conveying unit defines a first conveying path and a second conveying path. The first conveying path includes an upper path, a lower path positioned below the upper path, and a curved path connecting the upper path to the lower path. The second conveying path includes the lower path, and an extension path that is connected to the lower path and branches linearly in a direction different from the curved path.
The reading unit reads images from sheets conveyed along the first conveying path and second conveying path. More specifically, the reading unit has a first reading unit and a second reading unit. The first reading unit is disposed on the lower path and can read a first surface of a sheet conveyed along the lower path. The second reading unit is also disposed on the lower path and can read a second surface on the opposite side of the first surface of a sheet conveyed along the lower path. The first and second reading units are disposed at the same position along the lower path but on opposite sides (i.e., one above and one below).
In this conventional image-reading device, the conveying unit conveys sheets either along the first conveying path so that the sheets pass from the lower path to the upper path via the curved path, or along the second conveying path so that the sheets pass from the lower path onto the extension path. During this conveying process, the reading unit can read images from one or both surfaces of a sheet conveyed along the lower path, with the first reading unit reading an image from the first surface of the sheet and the second reading unit reading an image from the second surface of the sheet. The first conveying path is used for reading images from relatively thin sheets that can be conveyed along the curved path, and the second conveying path is used for reading images from thicker sheets that are not suitable for the curved path, for example.